Now that the dry summer is over, you may be thinking about filling in the bare spots on your lawn or starting over again from scratch. Or you should be.

September is the best time of the year to plant a new lawn, according to turfgrass professor Bridget Ruemmele, because the temperature is ideal, there are fewer weeds germinating, there is more moisture in the air and the lawn can strengthen further next spring before the stresses of the following summer.

“Fall is when your grass really grows, the roots grow, and it has a chance to get good and strong,” she said. “So you should really jump to it now. It’s also the right time to reduce thatch as well.”

If a new lawn is in your near future, there’s a good chance that you’ll see URI #2 grass seed for sale at your local garden store or hardware store. First created a half a century ago, URI grass seed mixes were developed for full sun (#1), sun and shade (#2) and low maintenance (#3). The mixes contained a certain ratio and minimum percentage of perennial ryegrasses, fine fescues, and Kentucky bluegrass.

Because the University has the oldest turfgrass research center in the country, seed companies wanted to use the URI name on their seeds to show that it met high quality standards.

“We don’t produce the seed here, but we license the right to use our name as long as they meet certain conditions,” said Ruemmele.

URI #1 and #2 seed mixes were upgraded in the early 1980s to include a certain percentage of improved seeds, and a plan is being developed to upgrade the mixes again. The new mixes will likely be required to contain a certain percentage of seeds determined by the National Turfgrass Evaluation Program to be disease and insect resistant and tolerant of reduced water and fertilizer.

If you decide to upgrade your lawn this fall – or any other time – Ruemmele recommends using only the quantity of seed recommended on the package.

“Using extra seed can actually be harmful to your lawn,” she said. “Often, people will try to get their lawn to grow fuller faster by increasing the amount of seed, but that just makes for too many plants competing for space and resources. You’ll just end up with unhappy results.”